The final death toll is expected to climb, but initial indications are that the government's evacuation of more than 600,000 people saved many lives. A cyclone of similar strength 14 years ago killed 10,000 people.

"Damage to property is extensive," said Amitabh Thakur, the top police officer in the Orissa district worst-hit by the cyclone, "but few lives have been lost."

After crossing the coast, the storm weakened considerably.

In the Orissa state capital of Bhubaneshwar, advertising hoardings and traffic lights were toppled across the city and trees were uprooted, but early reports indicated that it escaped major damage.

More than half a million people were evacuated from their homes in Orissa state, and 100,000 in neighboring Andhra Pradesh.

Officials in both states had stockpiled emergency food supplies and set up shelters. The Indian military put some of its forces on alert, with trucks, transport planes and helicopters at the ready for relief operations.

Save the Children said it was working with the Indian government and partners to assess the needs of children.

Spokesman Devendra Tak, in Puri, said: "There are no reports of casualties so far in the area, which is a good indicator although it is still early, so it's difficult to know the full extent of the damage."

Save the Children has emergency hygiene and food kits for families in most need.

Tak continued: "The hotel I stayed in was one of the tallest buildings in the area, so I could see far around. From here in Puri, the damage does not look as bad as we thought it could be: telephone posts have been pulled up from the ground, and trees uprooted, but buildings remain - for the most part - intact.

"Looking out to the ocean, it's clear the water is still quite rough. On the ground, people are starting to come out, there are children on the streets. The wind is still quite strong although the rains have let up.

"The wind speed is very high, so we anticipate that there may be delays in being able to reach the most vulnerable families with aid. This also means it could take some time before the full extent of the damage is known, but our teams are working around the clock to coordinate a rapid response and meet the needs of those affected."

A spokeswoman for Oxfam said the next few hours remained crucial for tens of thousands of Indians stuck in the middle of one of the country's largest natural disasters.

"The major challenge is to clear debris and to quickly restore communications. Oxfam India's staff will assess the situation as soon as possible. Oxfam India has contingency stock on standby for deployment to address vital water and sanitation needs and emergency shelter needs for over 30,000 people during the initial stage of the crisis."

Zubin Zaman, humanitarian programme manager of Oxfam India, said: "Roads are blocked by fallen trees, communication and power lines are down. Damage to buildings is widespread so is the impact on the crops of the region. There are reports of damage to fishing boats and nets of fishing communities in Puri and Ganjam.

"People have started returning to their villages from the shelter places. One of the immediate requirements for these communities is to restore their houses. Water and sanitation remains a major concern for the people living in the low lying areas as most of the drinking water sources have been contaminated because of heavy rains and storm surge."